This invention relates to a fluid control device having a reciprocating valve capable of digitally controlling the flow of fluid therethrough in which the point of digital actuation between "on" and "off" states can be controlled across a wide range of pressures and flow rates. Viewed in another sense, the prior art relates to magnetic relief valves employing therein such mechanical elements as diaphragms and spring bias ball checks with which to open or close responsive to small changes in fluid pressure.
In certain applications there is a need for a simple and relatively low cost valve that will actuate when the fluid flow pressure reaches an upper value and, similarly, that will reset when the fluid pressure falls to a lower value. Prior art in the present area is, to the best knowledge of the inventor, represented by U.S. Pat. Nos. 3,122,162 to Sands; 3,495,620 to Raimondi; 3,921,662 to Hauffe; 4,019,531 to Johnson; and 4,128,105 to Follett.
The present invention is believed to be properly classified in one or more of the following subclasses: U.S. Class 137, Subclasses 498, 517, 529; and U.S. Class 251, Subclass 30.